Air cooling system



g- 11, 7 L. NAGYSZALANCZY 3,523,428

AIR COOLING SYSTEM Filed Jan. 16, 1969 COLD LOW, PRESSURE AIR I COOLING AIR IN PRESSOR HIGH PRESSURE AIR TURBINE coou-e AIR OUT HEAT EXCHANGER FIG.1

mm H I N I II I m I I "HM \/I\ MN 5 I m I 6 I \IIIIIII X n-fi -v IIIP Q B I I II M Q a United States Patent "ice 3,523,428 AIR COOLING SYSTEM Lorant Nagyszalanczy, Sherman Oaks, Calif., assignor to The Garrett Corporation, Los Angeles, Calif., a corporation of California Filed Jan. 16, 1969, Ser. No. 791,580 Int. Cl. F25d 9/00 US. Cl. 62-402 11 Claims ABSTRACT OF THE DISCLOSURE An air cooling system having a source of pressurized air wherein the air is further compressed in a centrifugal compressor, cooled in a heat exchanger to ambient temperature, and then expanded through a turbine having two turbine spools which rotate at different speeds. The faster spool powers the centrifugal compressor while the slower spool operates a fan to move ambient coolant air through the heat exchanger.

This invention relates to an air cooling system and, in particular, to a system for reducing the temperature of air which system does not involve the use of a condensible refrigerant.

Air conditioning or cooling systems, as encountered on aircraft, utilize high pressure air, that is bled from the engine, to pressurize the cabin and supply fresh cool air to the passengers. The system includes a compressor to compress the bleed air, a heat exchanger to cool it to substantially ambient temperature, and a turbine to expand the air and transfer energy to the compressor. When the aircraft is flying, the coolant for the heat exchanger is ram air, but, when the aircraft is on the ground, fans are needed to move ambient air through the heat exchanger.

Therefore, an object of this invention is to provide an air cooling system of the type described having incorporated therewith means for moving coolant air through the heat exchanger.

A feature of this invention is the provision of a twospool turbine for an air cooling system wherein one spool operates an air compressor and the other operates a fan.

Another feature of this invention is a two-spool turbine having coaxial turbine wheels or rotors wherein the gas flows inwardly through one wheel and then through the other wheel. The outer wheel is of the impulse type having a limited angular speed at no load and the inner wheel is primarily of the reaction type to cause the inner wheel to rotate at relatively high angular velocities.

These and other objects and features of advantages of the present invention will become apparent from a review of the following description of a preferred embodiment and claims when taken in conjunction with the drawing, wherein:

FIG. 1 is a schematic embodiment of the novel air conditioning system; and

FIG. 2 is an enlarged detailed axial section of the rotating machine for the air conditioning system.

Referring to the drawing and to FIG. 1 in particular, a cooling system is shown having a compressor 11 and a fan 12 both of which are powered by a turbine 13. A shaft 16 transfers power from the turbine 13 to the compressor 11 while a shaft 17 transfers power from the turbine to the fan 12. The compressor 11 has an inlet 18 which is coupled, for example, to a source (not shown) of pressurized air which is at a relatively high pressure. The pressurized air is further compressed and the compressed air is discharged from the compressor 11 through an outlet 19. A heat exchanger 21 is coupled to the out- 3,523,428 Patented Aug. 11, 1970 let 19 and to an inlet 22 of the turbine 13 so that any fluid flowing out of the compressor enters the turbine after the fluid has been cooled within the heat exchanger, in a manner to be described hereinafter. The fluid expands within the turbine giving up energy to shafts 16 and 17, and then the fluid is discharged through an outlet 24 at a lower temperature and pressure than when it entered the turbine. Energy is transferred to the compressor 11 to compress the incoming bleed air, and enenergy is transferred to the fan 12. The fan 12 draws the coolant, for example, ambient air through an annular inlet 23 and discharges the air through an outlet 25 into an inlet duct 26 for the heat exchanger 21. The ambient air passes through the heat exchanger 21, where it picks up heat from the compressed air, described above, and the ambient air is discharged through an outlet duct 27.

As mentioned above, the function of the fan 12 is to move relatively large quantities of low pressure ambient air through the heat exchanger 21 while the function of the compressor is to further compress the high pressure air so that the heat exchanger can effectively remove internal energy therefrom. To substantially compress the high pressure air, the compressor should rotate at relatively high speed, much higher than the fan. The fan should rotate at a relatively low speed to maintain a low noise level and high efficiency. Referring to FIG. 2, there is shown an axial section of a preferred embodiment of the fan 12, turbine 13 and compressor 11. The compressor inlet 18 opens into a suitable housing for the compressor 11 wherein is disposed a rotating impeller 31 suitably fixed to one end of the shaft 16. The impeller 31 is of standard design for compressing air. At the other end of the shaft 16 is fixed an inner turbine rotor 32. The impeller 31, shaft 16 and rotor 32 form one of the rotating spools. The other rotating spool is formed by an outer turbine rotor 33 fixed on the shaft 17, and a fan hub 36 with blades 37 also fixed on shaft 17. The blades 37 are of a standard design for moving relatively large volumes of air. The compressor has a diffuser 39 opening into a scroll 41, as is standard in the art, so that the high velocity is converted to high pressure. The fans inlet 23, for simplicity of design, is preferably annular so that very little flow resistance is encountered. The inlet 23 is part of a contoured fan housing wherein the outlet 25 is axially disposed.

The turbine 13 is of the radial flow type and includes a suitable scroll 42 wherein the high pressure gas is distributed to suitable nozzles 43 that are distributed around the axis. The nozzles 43 are designed so that the velocity of the air exiting therefrom is substantially constant under wide load requirements. The outer rotor 33 is a standard impulse type that rotates under. all load conditions with a peripheral speed that is less than the velocity of the air exiting the nozzles 43. The air then enters inner rotor 32wherein the remaining energy in the air causes this rotor 32 to rotate. The inner rotor 32 is preferably of the reaction type, allowing this rotor to achieve .a very high angular velocity.

In the light of the above teachings, various modifications and variations of the present invention are contemplated that would be apparent to those skilled in the art without departing from the spirit and scope of the invention. Therefore, the invention is not limited to the exemplary apparatus or procedures described, but includes all embodiments within the scope of the claims.

What is claimed is: 1. In combination: first means for supplying compressed fluid,

second means for supplying a stream of cooling fluid, turbine means for driving both said first and second means,

third means for receiving both said compressed fluid and said cooling fluid to cool said compressed fluid with said cooling fluid,

fourth means for conducting said compressed fluid from said third means to said turbine means, and said turbine means having an outer Wheel and an inner wheel,

a first shaft connecting one of said wheels with said second means, and

a second shaft connecting said other wheel with said first means.

2. In the combination of claim 1 wherein said one wheel is of the impulse type so that its angular velocity is limited.

3. In the combination of claim 2 wherein said one Wheel is the outer wheel.

4. In the combination and inner Wheels rotate 5. In the combination and inner wheels rotate of claim 1 wherein said outer at ditferent angular velocities. of claim 2 wherein siad outer at different angular velocities.

6. In the combination of claim 3 wherein said outer and inner wheels rotate at different angular velocities.

7. In the combination of claim 1 wherein said first and second shafts are aligned.

8. In the combination of claim 1 wherein said one References Cited UNITED STATES PATENTS Welch 415-64 Kleinhans 62402 Mayer 6287 Messinger 62-402 Seeger 62402 Buchi 230131 20 WILLIAM J. WYE, Primary Examiner U.S. Cl. X.R. 

